Can anyone post a cutaway diagram of a 1926 headlamp bucket, reflector and bulb, with the correct positioning of how a 6v dual filament 50cp/32cp bulb is supposed to be positioned in the front of the reflector and showing the direction of the beam?
As you can see in the attached photo, one filament is the bright 50cp and the other is the dim 32cp. the longer filament juts out further and is offset, while the other filament is shorter and is positioned in the center of the bulb. I am unsure of how it goes into the socket so that the beams are correctly reflected. I suspect that the shorter centered filament is the bright filament with the beam reflecting equally all around while the longer offset filament is the dim filament that is positioned so that the offset filament, being positioned closer to one side of the reflector is focused in a certain direction, but this is just a theory. Has anyone had any experience with the installation of the dual filament 50/32 bulbs? I have been searching the forum for days trying to find the answer and am surprised this has never come up, or, if it has, that I am unable to find it in past threads. Thank you. Jim Patrick
Park your car in front of the garage or a wall and observe the light pattern. Choose the position you like best. Based on past experience,I don't think you will see a lot of difference. You will probably gain more by adjusting the lamp socket in and out with the focus crew.
With incandescent 6 volt Model T lamps the headlight intensity varies from so-so to not so hot. Nothing dramatic should be expected.
Jim, I believe that the bulbs you show are stop/tail light bulbs. Headlight bulbs have a broad flat front face and appear more triangular than round. The old bulbs were the same candlepower on both filaments, they did not get any brighter but the focus of the beam changed through the lens. The filaments were horizontal, one on top of the other and the position made the angle of the reflection change so that there was a "HIGH" beam and a "LOW" beam. The lights appear brighter to oncoming traffic, but that is only due to the fact that the light is shined higher and farther down the road.
You will never be able to focus those stop/tail bulbs because one filament is farther ahead of the other.
Wire them up and put the bulbs in and turn them on Hi beam, if one bulb shows less light then turn it half way and re install. if there on low with sw. in Hi turn the plugs (in Back) half way and re install. Hope this helps.
Here is what Bob Blackbourn wrote at:
"Schuh, yes the filaments need to be horizontal. Look closely at the lamp and you will see that one filament is centered in the bulb. This is the bright filament. Place the lamp in the holder so that the "Dim" filament is below the bright filament. You may have to reverse the position of the plug to get the filaments lit in the correct order.
When you get them installed check the aim against a wall at night. With the switch in the "on" position, turn the adjusting screw to focus the beam. The beam should be lower with the switch in the "Dim" position. I found it easier to unplug one light while focusing and aiming the other.
Sounds reasonable to me.
How do you guys feel about the halogen bulbs available for the Model T? Any opinions as to positives or negatives from experience?
Jim ; Put in one bulb at a time and look what the amp. meter say. More amp. is bright light .
Jim, you don't say if your 1926 is early or has the light bar across the front.
As near as I can tell there is no way to properly focus the early 1926 headlights, as there is no left and right headlight and those headlights were used on an early truck that had the mounting straight down, instead of at the fender angles.
That was an early service change that never generated a recall, like it should have done.
I say again, those are NOT headlamp bulbs! You will never get them in focus with one filament ahead of the other. Even the halogen bulbs have equal filaments as can be plainly seen on Snyders website. They also have the proper standard bulbs, as do all of the vendors.
This came up in another thread recently. I mentioned there that something called the LCL length governs 'how things work' in the parabolic reflector.
MAZDA Lamp Co. at the time claimed their 1000 lamp (32/32)and 1110 lamp (21/21) (Both dual filament type) were interchangeable with the OEM Ford lamps. Marketing puffery or true? I don't know.
Point being we don't know the Ford LCL number, but these MAZDA lamp numbers were part of the standardized system and the LCL length is known. The LCL is 1.25" for the #1000.
Match the LCL with any other lamp combination, you match the parabolic reflector in the T within the normal adjusting screw travel.
Jim Patrick's bulbs will work just fine. We are not dealing with precision optics or a point source, its just a Model T headlamp. All this about getting everything just so is really just wandering in the noise.
James, My Coupe was manufactured in March of 1926 and does have a light bar. Jim Patrick
That's the whole point Ted, it is precision optics. When the filament is in the correct position the light rays are reflected off of the reflector at a slight downward angle to the street in front of the car. The fluted lens further bends and focuses the beam to a broad flat beam that spreads the light and does not shine into the eyes of oncoming traffic. When you switch to "HIGH" beams, the other filament which is in a slightly different position in relation to the reflector is illuminated and the light rays are reflected higher, or farther down the road. that is why they are called "HIGH" beams. High beams are not necessarily brighter, in fact they weren't any brighter originally although dual candlepower bulbs are now available, but they appear brighter because they shine farther down the road, and also they appear brighter to oncoming traffic because they are shining in their eyes.
If Jim uses those tail light bulbs, they will produce light, but they will not shine where they need to shine, and he most likely will not be happy with the results, and neither will other drivers. The correct bulbs are available, why not use them?
Thank you Jeff, but are you sure the bulbs I have are just for tail lights? I don't see where the shape of the glass bulb (round, as opposed to triangular) has anything to do with the function of the bulb. I have seen modern headlight bulbs shaped like this and they worked just fine and 50cp/32cp seem awfully powerful for tail lights. Original Model T headlight bulbs were just 21cp and these are twice as bright on brights and 1 1/2 times as bright on dims, which, on today's roadways are necessary as the original 21cp dual filament bulbs barely light up the road in front of me and I can see no difference between brights and dims, so it is a safety issue with me, just to be able to see where I am going and for other drivers to see me coming (My Mag and generator are working perfectly).
I will try these using the suggestions in the thread Jim Thode posted (thank you Jim. That is what I was searching the archives for) and keep you all posted as to the results I get in focusing them onto my white garage door at night parked 25' from the headlight lens to the chart I mark on the door as per the Ford Model T Service Manual. Who knows...if they work, I may start a whole new trend Jim Patrick
I have both the low and high filaments lit at the same time. Looks bright as heck standing in front. I haven't tried them on the road yet. I have a 12 volt system and alternator so i am not worried about current draw.
I don't see why any Model T owner would ever need any thing brighter than a 32 cp bulb!
Why should a Model T be expected to use a less efficient light than any modern day car when driving on modern roads at night, just because it originally used 21cp bulbs, which are not sufficient for today's highways? I would expect we would want to see and be seen just as well as other drivers on the highway.
Modern bright and dim sealed beam headlights are much brighter and shine much further than the original 21cp/21cp or even the 50/32cp bulbs I am advocating and most people drive using the dims anyway, unless they need the brights to see further ahead in emergencies, so why criticize the use of a bulb that provides one with a more suitable 32cp for dims and a more adequate 50cp for brights?
The Model T, while more primitive than modern cars should not be made intentionally more unsafe just because using a brighter bulb would somehow, make it less original or more like a modern car. With today's traffic, which travels almost 3 times faster than the model T, it only stands to reason that it should be made more, not less, visible from a further distance away by fast approaching cars, especially if an oncoming car has the intention of passing a car in their lane and cannot see the dim 21cp lights of the approaching Model T in the oncoming lane until it is too late. Jim Patrick
Jim, I don't think that the shape of the bulb matters all that much. Snyders and probably all of the rest of the vendors have headlight bulbs in 32-50c ratings. The main problem you will have with your bulbs will be focus. There was a thread on headlights last month with a good illustration towards the end showing how the position of the filament, the LCL as mentioned above, affects the angle of the reflected light. Using your bulbs, with one filament nearly a quarter of an inch farther forward and also nearly a quarter of an inch higher or lower depending on how you install it, you will never be able to focus both beams with any satisfaction. If you are even able to get one beam in focus, the other will be WAY off. Check the illustration near the end of this thread. http://www.mtfca.com/discus/messages/331880/368621.html
Thanks Jeff. I see what you mean. Since there is only one adjustment screw, while you get one filament adjusted perfectly, you might have trouble adjusting the other one, if the filaments are not the same length.
Hopefully that will not be the case. I will be going into this assuming that the center, shorter filament is the bright beam and the longer, offset one is the dim beam. Since I will most likely be driving using the 32cp dims, I will adjust the LCL for that properly and see where the brights end up.
I'm hoping that the longer filament was an advanced improvement on the original, equal distanced filaments design and they can both be adjusted to their maximum efficiency with the same adjusting screw. Keep in mind that the longer filaments' LCL on the close side is further out than the LCL on the far side, which might serve to even out the beam, whereas, if the filaments were equal, the LCL of the longer filament on the far side, might be too close to even reflect on the far side which would make for an uneven beam. Just a cockamamy theory that makes sense only to me. . Jim Patrick
The contacts in the socket put the filaments of the modern replacement bulbs in the wrong direction. The Modern bulb bought through most suppliers put into the Model T socket put the filaments in a vertical rather then horizontal position. So the discussion about the reflector and lens is moot unless that problem is addressed.
Mark. Looking at the filaments compared to the contacts, it does appear that the filaments will be side by side as opposed to above and below eachother as you advocate. What do you suggest should be done to correct this? I assume that it would not be practical to twist the socket 90 degrees due to the position of the focusing screw, therefore, can new lock lugs be made from small nails of the same diameter as the locking lugs on the bulbs and be repositioned at 90 degrees then secured with solder? Jim Patrick
Nevermind. If I did that, the bulb contacts would not be in line with the socket contacts. At least I saw it before one of you corrected me on it (for once). LOL! Jim Patrick
Just put the bulbs in and set the focus using the pattern on your garage door.
Jeff, it is optics but its not precision. Model T headlights with 6 volt incandescent bulbs will give you are working headlight, but its not going to be fantastic. In the fifties, when I got my Model T inspected, the requirement was the lights had to score at least "poor" on the intensity meter. They did that and no more.
The lights on my touring are the best they have ever been on either of my Model T's. They are 12 volt 1157, 21 cp parking light bulbs. At speed with the alternator they are a pretty decent headlamp.
Here is a photo of an original Ford Script 21-3 cp bulb. The bottom contacts are not round, but kidney shaped. This bulb was manufactured by Tung Sol, but there is no bulb number.
I apologize. The above bulb is a 21-2 cp.
Boy, who would ever thunk it? Changing those Model T headlight bulbs is really complicated. With all this hoopla, Congress must be in the middle of it somewhere.
On another note, if you ever want to look into an energized bulb to see which filament is burning, a welding shield works great.